In ectothermic vertebrates (lizards) temperature plays an integral role in determining the rate at which responses to internal and external stimuli occur. Hyperthermia after parietal eye or pineal body ablation suggests that, in reptiles, these brain structures secondarily influence physiology and behavior by controlling the selection of appropriate body temperatures. This project examines the levels of body temperature which permit the expression of species-typical behavior and physiology in animals lesioned during neonatal development.